DPMO in Complex Machining Operations

Paul,

The logic in the referenced link is exactly right. They are giving one opportunity for each thing that must be right. One opportunity for each solder joint, one opportunity for each componenet. Note that even though the author says opportunity for defect, he is actuall counting each thing which must be right (not inflating the number for each thing we can imagine will go wrong).

For machining, the logic is the same. Look at everytime a machining process changes the product toward its final state. This is from the products point of view. For example, the product goes through a broaching operation, it is changed - one opportunity. The product is transported or stored or mounted or tested, it is not changed - no opportunity. In the case of complex tools, count opportunities as if each thing done by the complex tool was done by single simple tools.

If you want to post a simple and a complex example to walk through, I will walk you through it.

Gary